NIST researchers have developed a compact optical platform that cools and traps gaseous atoms in a 1-centimeter-wide region, a key step toward employing ultracold atoms in compact, chip-based navigation and quantum devices outside a laboratory setting. The new system, while still about 10 times too big to fit on a microchip, is a proof of principle that miniaturized laser cooling is possible.
The apparatus consists of three optical elements: an extreme mode converter, a metasurface, and a diffraction grating. The converter enlarges a narrow laser beam to efficiently interact with and cool a large collection of atoms. The metasurface further widens the beam and reshapes the light, creating a uniform brightness across its entire width. The diffraction grating splits the single beam into four pairs of equal and oppositely directed beams that serve to trap the cooled atoms.
While the optical system will need to be 10 times smaller to laser-cool atoms on a chip, the experiment demonstrates that miniaturized laser cooling is feasible. This breakthrough could enable laser-cooling based technologies to exist outside of laboratories, opening up new possibilities for highly accurate navigation sensors, magnetometers, and quantum simulations.
Keywords: Laser cooling, Ultracold atoms, Metasurface, Magneto-optical trapping, Quantum devices
